1. Field of the Invention
Embodiments of the present disclosure generally relate to power conversion and, more particularly, to preventing photovoltaic cell reverse breakdown during power conversion.
2. Description of the Related Art
Solar panels have historically been deployed in mostly remote applications, such as remote cabins in the wilderness or satellites, where commercial power was not available. Due to the high cost of installation, solar panels were not an economical choice for generating power unless no other power options were available. However, the worldwide growth of energy demand is leading to a durable increase in energy cost. In addition, it is now well established that the fossil energy reserves currently being used to generate electricity are rapidly being depleted. These growing impediments to conventional commercial power generation make solar panels a more attractive option to pursue.
Solar panels, or photovoltaic (PV) modules, convert energy from sunlight received into direct current (DC). The PV modules cannot store the electrical energy they produce, so the energy must either be dispersed to an energy storage system, such as a battery or pumped hydroelectricity storage, or dispersed by a load. One option to use the energy produced is to employ one or more inverters to convert the DC current into an alternating current (AC) and couple the AC current to the commercial power grid. The power produced by such a distributed generation (DG) system can then be sold to the commercial power company.
PV modules generally comprise one or more sets of PV cells connected in series for generating DC current from received solar irradiance. Each series-connected PV cell shares the same current, where the current at a given voltage is roughly proportional to the solar irradiance received by the PV cell. Under some conditions, one or more PV cells may become partially-shaded and unable to pass the global current produced by other PV cells within the set unless the shaded PV cell is forced into reverse breakdown. During such operation, the partially-shaded PV cell must dissipate a large amount of power, possibly leading to increasing temperatures at “hot spots” within the PV cell and potentially destroying the PV cell. Bypass diodes are typically utilized to protect the PV cells from such damage; however, the use of bypass diodes increases the number of components and connections required for operating a PV module.
Therefore, there is a need in the art for a method and apparatus for preventing PV cell reverse breakdown during power conversion.